Archival libraries typically comprise media cartridges that are used to store data. Such libraries often include a mechanism that is used to select cartridges housed in the library, and insert them into a media drive of the library for writing or reading of data. In such cases, once the writing or reading has been completed, the mechanism removes the media cartridge from the drive, and places it back in a storage location of the library for later use. One example of such an archival library is an optical library that includes cartridges that each contain a high-density optical disc. Many such optical libraries comprise so-called magneto-optical (MO) cartridges that contain optical discs that are written to using a magnetic field.
Magneto-optical libraries have been used for several years. Over that time period, MO cartridges having been developed that have greater and greater storage density. It appears now, however, that the limits of the MO technology have nearly been reached. Due to the perceived storage density limitations of the MO technology, a new form of storage media, referred to as ultra density optical (UDO), has been developed. With UDO technology, an optical disc whose state can be changed using laser beam pulses is provided in each media cartridge (i.e., UDO cartridge). Because of the greater storage density of UDO discs, UDO cartridges are available that, although roughly the same size as MO cartridges, have several times the storage capacity of the highest capacity MO cartridges.
It is unlikely that UDO cartridges will immediately replace MO cartridges, at least in part because many users still possess MO-based libraries and/or MO cartridges. In appreciation of this fact, several library manufacturers are now developing libraries that use both MO and UDO cartridges.
Because the MO and UDO technologies use different methods to write and read data, MO and UDO technologies are not compatible. Therefore, MO and UDO drives must be provided in libraries that accept both MO and UDO cartridges. Due to the incompatibility of MO and UDO cartridges, it is necessary for the library to identify the cartridge type for each cartridge within the library. Without such identification, mis-insertion of cartridges could occur, resulting in errors that may require a time-consuming recovery process and, potentially, human intervention.